The present invention relates to a tower for exploiting fluid through an expanse of water, comprising:
a fluid transporting pipe, designed to be submerged in the expanse of water, the transporting pipe including a lower section designed to be connected to a bottom assembly producing fluid, a flexible upper section designed to be connected to a surface assembly, and an intermediate section placed between the upper flexible section and the lower section;
an element for anchoring the transporting pipe to the bottom of the expanse of water, connected to an upstream point of the intermediate section;
a buoy designed to be completely submerged under the surface of the expanse of water, the buoy being connected to a downstream point of the intermediate section to keep the intermediate section situated between the downstream point and the upstream point in a substantially vertical configuration under tension,
the buoy having a height, considered along the vertical axis, less than 1.5 times its maximum transverse direction, the buoy delimiting a first through passage in which the intermediate section is engaged.
Such towers are designed to transport a fluid produced in the bottom of the expanse of water up to the surface, through the expanse of water. This fluid is in particular made up of liquid and/or gaseous hydrocarbons and water collected in production wells formed in the bottom of the expanse of water.
Such a tower generally has a lower connecting pipe for connecting to the production assembly positioned on the bottom of the expanse of water, a substantially vertical riser, a buoy for keeping the riser under tension in its vertical position, and an anchoring element for a lower point of the riser.
The tower further comprises an upper flexible connecting pipe connecting the riser to a floating surface assembly.
Thus, the hydrocarbons produced by the bottom assembly are successively transported through the lower connecting pipe, the riser and the upper connecting pipe as far as a surface assembly, such as a vessel, a platform or a barge, where they can be recovered or transported.
This type of tower has a relatively simple structure, since its maintenance in the vertical position is ensured exclusively by the anchoring element in the bottom of the expanse of water, and by the tension created by the buoyancy of the maintaining buoy connected to the upper point of the riser.
A tower of the aforementioned type is for example described in GB 2,024,766.
However, such towers remain difficult to install, in particular due to the depth of the expanse of water, as well as the movements on the surface of the expanse of water due to the swell and/or wind.
Furthermore, the deployment of the riser and the upper flexible pipe, and their connection on the buoy, are difficult to perform.
In particular, the upper flexible pipe is generally connected on the riser by means of a connecting section in the form of a gooseneck. This connection is done in the expanse of water after the installation and submersion of the buoy, which makes the connection operations very complex.
One aim of the invention is therefore to obtain a tower for transporting fluid through an expanse of water with a simple structure and that is easy to install, in particular at great depths or when the expanse of water is agitated.